stop when youve had enough hint...
see how leonard appears to be squinting to check something in the distance before he bets?
maybe hes looking at something that's helping him win?
something reflective maybe?
(the clown nose above the door, maybe?!)
how could Sam sabotage Leonard looking at his reflection to see his card?
maybe you could block it out, or change what card leonard thinks he has?
maybe another card?
get the ace of spades from the floor in your office, and stick it on the clown nose. then leonard will always think he has the ace of spades and bet it all, even if he has a low card